Crouch, H. W.

Peterson, N. E., Jr.

English

NASA Technical Reports Server

Oct. 12, 1965 JAMES E. WEBB 3,211,169 
ADMINISTRATOR O F  THE NATIONAL AERONAUTICS 
AND SPACE ADMINISTRATION 
SHRINK-FIT GAS VALVE 
Fi l ed  Oct. 1, 1963 
FIG 1 
https://ntrs.nasa.gov/search.jsp?R=19700025771 2020-03-17T02:03:36+00:00Z
3,211,169 United States Patent Office patente, .,. ,, ,, 
1 2 
portion 21 and is adapted to be operated by an actuating 
3,211,169 mechanism (not shown). 
SHRINK-FIT GAS VALVZ Seat body 12 of valve seat 11 and plug 10 of mating 
James E. Webb, Administrator of the National Aeronau- member 19 are made from materials having different tics and Space Administration with respect to an inven- coefficient of thermal expansion, such as different stain- tion of Hasell W. Crouch, 12419 Starlight Lane, Bowie, less steels, with the seat body 12 having the greater co- Md., and Norinan E. Peterson, Jr., 5638 Emerson St., 
Bladeusburg, Md. efficient of thermal expansion. Alternatively, seat body 
Filed Oct. 1, 1963, Ser. No. 313,135 12 and plug 10 can each be made of materials having the 
2 Claims. (Cl. 137-340) same coefficient of thermal expansion as long as a tem- 
10 perature difference is maintained therebetween by, for 
The present invention relates to an improved valve for example, heating elements in each member. The seat- 
a vacuum system, and more particularly, to an improved sealing and mating surfaces of cylindrical portion 16 of 
gas valve wherein a seal is formed by joining two pieces aperture 14 and cylindrical portion 21 of plug 10, re- 
of material by a shrink-fit or expansion-fit method. spectively, should have a high polish, mirror-like finish. 
As will be readily observed, the valve described here- 15 While aperture 14 is shown having a cylindrical portion 
inafter, possesses advantages over prior art valves by be- 21, these portions may alternatively be any round or 
ing more durable, and by not having a tendency to break elliptical configuration. Funnel portion 17 acts as a guide 
down. It  also has the advantage of achieving an excel- means to permit plug 10 to be easily inserted into or re- 
lent seal without the use of gaskets such as 0 rings. In moved from aperture 14. 
fact, it will maintain an effective seal against atmos- 20 The gas valve of the present invention as shown in 
pheric pressure to a pressure at least as low as mil- more detail in FIGURE 3 comprises valve seat 11 of 
limeters of mercury. In addition, since the valve ele- FIGURE 1 and mating member 19 of FIGURE 2 operat- 
ments, in operation, do not relay on a friction fit and do ing in conjunction with each other and formed as an 
not need to rub against each other, there is little wear integral part of plumbing 24. The gas valve controls the 
due to friction. Further, the particular operation of the 25 fluid (gas) flow between inlet-outlet end 27 of plumbing 
valve results in its being suitable for use where continuous 24 and vacuum chamber 25. Stem 23 of mating member 
functioning is desired. 19 is connected to plumbing 24 by metal bellows seal 26. 
The valve of the instant invention comprises an outer This seal prevents leakage from the plumbing while at  
valve seat member having a heating element formed as the same time permits movement of plug 10 relative to  
an integral part thereof and an aperture passing there- 30 aperture 14 of valve seat 11. Power source 18 is con- 
through, the aperture possessing a highly polished, seat- nected through control means 20 to electric heating ele- 
sealing surface; and an inner mating member having a ment 13. Control means 20 can be, for example, a poten- 
stem or actuating arm and a plug attached thereto, the tiometer, a switch (either mechanical or electronically 
plug having a correspondingly highly polished, mating operated), etc. 
surface. The outer member and inner member are 35 The following is a description of the operation of the 
adapted to be joined and are sealed together by the use gas valve shown in FIGURE 3. Control means 20 con- 
of a shrink or expansion-fit technique. By introducing nects power source 18 to electric heating element 13, 
heat to the outer member from the heating element, the which in turn s~~pplies heat to seat body 12 of valve seat 
outer member expands sufficiently so that, by operation 11 to achieve sufficient expansion thereof to allow plug 
of the stem, the plug portion of the inner member is per- 40 10 to be inserted into aperture 14. By an actuating means 
mitted to be inserted into the aperture thereof. Upon the (not shown), stem 23 inserts plug 10 into aperture 14 
removal of heat from the outer member, the aperture of valve seat 11 such that the seat-sealing surface of 
therein shrinks and the seat-sealing surface thereof makes cylindrical portion 16 of aperture 14 makes contact with 
intimate contact with the mating surface of the plug of the mating surface of cylindrical portion 21 of plug 10. 
the inner member to  form a shrink-fit therebetween. 45 Intimate contact between these surfaces results after valve 
When the heating element is again energized, the aper- seat 11 is cooled; and a shrink-fit coupling is obtained 
ture expands and allows the plug of the inner member wherein full circumference of the valve connection is 
to be withdrawn therefrom. maintained under compression to achieve a good vacuum 
The exact nature of this invention, as well as other tight seal. Plug 20 can be withdrawn from aperture 14 
objects and advantages thereof, will be readily apparent 50 if heat is again applied to seat body 12 of valve seat 11. 
from consideration of the following specification relating In this particular embodiment of the invention, power 
to the annexed drawing in which: is only applied to the heating element when it is desired 
FIGURE 1 is a sectional view of the outer member of to open or close the valve (remove or insert the plug 
the gas valve of the invention; in the aperture). When the valve is maintained in its 
FIGURE 2 is a front view of the inner member of the 55 closed and sealing condition, there is no power applied 
gas valve of the invention; to the heating element. It  is important to note that t o  
FIGURE 3 is a sectional view of a preferred embodi- maintain good operation of the gas valve the materials 
ment of the invention; and comprising it should not be compressed beyond their yield 
FIGURE 4 is a sectional view of another embodiment stress. 
of the inner member having temperature variation means 6O Should it be desirable to continually open and close the 
cooperating therewith. valve, then valve seat 11 would be alternatively heated 
Referring now to the drawing, there is shown in FIG- and cooled. By such an operation of this gas valve, gases 
URE 1 an outer valve seat member 11 comprising seat can be continually exhausted from vacuum chamber 25 
body 12 having electric heating element 13 contained to form a vacuum (therein with the valve itself, in its 
therein and an aperture 14 substantially in the center 65 closed condition, acting as the gas seal. 
thereof. Aperture 14 includes a cylindrical portion 16 While the above description describes the operation 
having a highly polished, seat-sealing surface located be- of a gas valve in terms of alternatively heating and cool- 
low and coaxial with large funnel shape guide portion 14. ing seat body 12 of valve seat 11, the valve would func- 
In FIGURE 2 there is shown inner mating member tion equally as well if plug 10 of mating member 19 
19 comprising a plug 10 including cylindrical portion 21 70 were alternatively heated ,and cooled instead. I t  is also 
having a highly polished, mating surface. Stem (actuat- possible to  utilize a combination of heating one of the 
ing arm) 23 is connected to and coaxial with cylindrical elements or cooling the other. Temperature regulating 
3,211,169 
3 4 
means other than electrical elements will work equally second member having an enlarged end poppet portion 
as well. They may include a piping with a fluid passing of slightly greater dinlension than said orifice and with 
therethrough to heat or to cool either of the members of an outer mating surface for sealing said orifice when said 
the valve. valve is in its closed condition; an electrically operated 
By properly controlling the tolerance of the valve seat temperature means contained within said first member; 
and plug and by properly selecting the materials thereof a second temperature means cooperating with said second 
so that they will have a desired difference in coefficient member; and control means coupled to both of said 
of thermal expansion, the environment wherein the valve (temperature means to control both of said temperature 
is to be used can be heated to a very high temperature to means so as to simultaneously regulate the temperature 
permit surface degassing of the vacuum chamber and of said first member and said second member to permit 
valve without affecting the valve seal itself. However, said end poppet portion to be inserted into said orifice 
when the valve is designed for this high temperature de- and to achieve a pressure seal between said seat-sealing 
gassing operation, the valve temperature must be in- surface and said mating surface. 
creased above the degassing temperaiure before the valve 2. In a pressure valve: a first member having an orif ce 
seal will be broken to allow the valve to be opened. therein with a seat-sealing surface; a second member of 
Alternatively, where it is desired that the valve seat l5 slightly greater dimension than said orifice and having 
and plug be made of materials having the same thermal an outer mating surface; actuating means connected to 
coefficient of expansion, ithe plug should contain a cooling said second member for applying reciprocating motion to 
means (see FIGURE 4 to be described in more detail said second member; electrical temperature means con- 
hereinafter) to permit shrinking it, thereby breaking the tained within said first member; second temperature means 
seal and allowing the valve to be opened. This will per- 20 associated with said second member; and control means 
mit the valve to be taken to high  temperatures for surface coupled to both of said temperature means to operajte 
degassing, limited only by the properties of the material them simultaneously for obtaining a temperature differ- 
used. ential between said first and second members to cause a 
Should it be desired that mating member 19 be heated variation in size thereof so that said second member can 
or cooled, then, as shown in FIGURE 4, a fluid from 25 either be inserted into or withdrawn from said orifice 
a source of fluid 36 can be discharged into circulating by said actuating means and for obtaining equalization 
system 35 contained within stem 23 and plug 10 of mat- in temperature of said first and second members so that 
ing member 19. By controls 37 and 38, the temperature said seat-sealing surface and said mating surface can 
of the fluid applied to circulating system 35 can be regu- make an intimate contact and form a pressure seal. 
lntprl 30 
*'L%*V. 
The foregoing disclosure relates to lthe pertinent em- References Cited by  the Exaznfner 
bodiment of the invention. Numerous modifications or UNITED STATES PATENTS 
alterations may be made therein without departing from 2,132,262 Gabriel ---- 137-340 
the spirit and scope of the invention set forth in the 35 2,994,338 8/61 Wilson --- 137-340 
appended claims. 3,028,874 4/62 Burkett -------------- 137-340 
What is claimed is: 3,101,094 8/63 McICenzie ---------- 251-157 X 
1. A reciprocating valve comprising a first member 
having an orifice therein with a seat-sealing surface; a ISADOR WEIL, Prin~nry Exnnziner. 


Shrink-fit gas valve Patent

Abstract

Similar works

Full text

Available Versions

NASA Technical Reports Server